Elevated lipoprotein(a) (Lp[a]) is the most common inherited dyslipidemia that is independently and causally associated with increased atherosclerotic cardiovascular disease (ASCVD) risk. However, data from diverse populations with ASCVD are lacking. To evaluate Lp(a) levels in a diverse, contemporary United States (US) population with ASCVD, stratified by race, ethnicity, and sex. Lp(a)HERITAGE (NCT03887520) was a multicenter study that estimated the prevalence of elevated Lp(a) in adults (18-80 years) with ASCVD. US participants with Lp(a) measured in nmol/L pre- or post-enrollment were included in this subanalysis. This study was descriptive; therefore, no statistical comparisons were made. Of all US participants, 14% had an Lp(a) measurement pre-enrollment. This subanalysis included 7679 US participants with Lp(a) measurements in nmol/L (80.5% White; 66.4% male; mean age 63.8 years [standard deviation ± 9.7]). Median Lp(a) was > 2.5-fold higher in Black participants (132.0 nmol/L; IQR, 57.1-239.6) vs the overall population (52.1 nmol/L; IQR, 15.7-167.8), and higher in females compared with males (69.4 nmol/L; IQR, 20.1-194.7 vs 45.6 nmol/L; IQR, 14.0-152.6, respectively). Lp(a) levels ≥ 125 nmol/L were more prevalent among Black (52.0%) and female (38.9%) participants vs the overall population (33.3%). In US Lp(a)HERITAGE participants, only 14% had an Lp(a) measurement pre-enrollment, despite having ASCVD. One-third of participants demonstrated Lp(a) levels ≥ 125 nmol/L, the threshold for high ASCVD risk, which was higher among Black (1/2) and female (2/5) participants, suggesting a greater need for Lp(a) testing in these groups to inform ASCVD risk mitigation.